From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Sun Feb 04 2007 - 02:50:59 ART
Below is the output from the debugs. You'll notice that when the static
route points to the interface that you will get an encapsulation failed
message but with the static route pointing to the remote end or a
frame-relay mapping for the destination the pings will be successful.
Rack1R1#show ip route
Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter
area
* - candidate default, U - per-user static route, o - ODR
P - periodic downloaded static route
Gateway of last resort is 0.0.0.0 to network 0.0.0.0
173.12.0.0/24 is subnetted, 1 subnets
C 173.12.23.0 is directly connected, Serial0/0
S* 0.0.0.0/0 is directly connected, Serial0/0
Rack1R1#debug ip packet
IP packet debugging is on
Rack1R1#ping 173.23.23.5 repeat 2
Type escape sequence to abort.
Sending 2, 100-byte ICMP Echos to 173.23.23.5, timeout is 2 seconds:
IP: tableid=0, s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), routed via
RIB
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100, sending
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100,
encapsulation failed.
IP: tableid=0, s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), routed via
RIB
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100, sending
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100,
encapsulation failed.
Success rate is 0 percent (0/2)
Rack1R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Rack1R1(config)#int s0/0
Rack1R1(config-if)#frame-relay map ip 173.23.23.5 105 b
Rack1R1(config-if)#^Z
Rack1R1#ping 173.23.23.5 repeat 2
Type escape sequence to abort.
Sending 2, 100-byte ICMP Echos to 173.23.23.5, timeout is 2 seconds:
!!
Success rate is 100 percent (2/2), round-trip min/avg/max = 32/34/36 ms
Rack1R1#
IP: tableid=0, s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), routed via
RIB
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100, sending
IP: tableid=0, s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), routed
via RIB
IP: s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), len 100, rcvd 3
IP: tableid=0, s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), routed via
RIB
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100, sending
IP: tableid=0, s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), routed
via RIB
IP: s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), len 100, rcvd 3
Rack1R1#
Rack1R1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Rack1R1(config)#int s0/0
Rack1R1(config-if)#no frame-relay map ip 173.23.23.5 105 b
Rack1R1(config-if)#exit
Rack1R1(config)#no ip route 0.0.0.0 0.0.0.0 s0/0
Rack1R1(config)#ip route 0.0.0.0 0.0.0.0 173.12.23.5
Rack1R1(config)#^Z
Rack1R1#ping 173.23.23.5 repeat 2
Type escape sequence to abort.
Sending 2, 100-byte ICMP Echos to 173.23.23.5, timeout is 2 seconds:
!!
Success rate is 100 percent (2/2), round-trip min/avg/max = 36/38/40 ms
Rack1R1#
IP: tableid=0, s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), routed via
RIB
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100, sending
IP: tableid=0, s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), routed
via RIB
IP: s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), len 100, rcvd 3
IP: tableid=0, s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), routed via
RIB
IP: s=173.12.23.1 (local), d=173.23.23.5 (Serial0/0), len 100, sending
IP: tableid=0, s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), routed
via RIB
IP: s=173.23.23.5 (Serial0/0), d=173.12.23.1 (Serial0/0), len 100, rcvd 3
Rack1R1#
--Brian Dennis, CCIE4 #2210 (R&S/ISP-Dial/Security/SP) bdennis@internetworkexpert.com Internetwork Expert, Inc. http://www.InternetworkExpert.com Toll Free: 877-224-8987 Direct: 775-745-6404 (Outside the US and Canada)
On 2/3/07 9:42 PM, "Brian Dennis" <bdennis@internetworkexpert.com> wrote:
> <quote> > Because as I understand, R1 will send the packets for any destination to R5 > </quote> > > The problem is that you are not sending packets for any destination to R5. > You are sending packets for any destination out Serial0/0. If Serial0/0 is a > point-to-point interface then it will be sent to the remote end-point. This > is because there can only be one 3 to layer 2 mapping on a P2P interface and > because of this all packets use that layer 3 to layer 2 mapping. > > If Serial0/0 is a multipoint interface (i.e. physical Frame Relay interface or > multipoint subinterface) then there can be more than one remote end-point and > hence more than one layer 3 to layer 2 mapping. In this case the router does > not have a layer 3 to layer 2 mapping for the destination (173.23.23.5) and in > turn drops the packet. To resolve this you can either configure the static > route to point to R5's IP address across the Serial0/0 interface (preferred > solution) or create a layer 3 to layer 2 mapping for 173.23.23.5 on the DLCI > to R5. > > The general rule is that when using static routes in a WAN environment you > shouldn't point the static route to an interface if it is a multipoint > interface.
This archive was generated by hypermail 2.1.4 : Thu Mar 01 2007 - 07:38:45 ART